This invention concerns a rolling unit having its rolls supported as cantilevers. To be more exact, the invention concerns a rolling unit which has its rolls supported as cantilevers and is suitable to enable maintenance or replacement of the rolls and/or equipment to be carried out in very short times during rolling operations.
Rolling units supported as cantilevers are known, as also are devices to replace the rolls and/or equipment on rolling stands having their rolls supported as cantilevers, such devices comprising:
a frame with connection means, PA1 jaws with engagement means, and PA1 actuation means,
the reciprocal positioning of the parts when engaged by such devices being substantially the same as the reciprocal positioning of such parts when fitted to a rolling unit.
EP-A-0142879 in the name of the present applicant should be consulted in this connection.
Such devices to replace the rolls and/or equipment enable action to be taken to reset the machine in very short times of the order of seven to ten minutes. This means that, if the personnel employed for the purpose are ready, some seven to ten minutes will go by between the time when the machine stops processing one section and the time when the machine is ready again to process the section programmed thereafter.
Such time of engagement of the rolls seems in itself to be unimportant but in fact may be very irksome.
Indeed, when small lots are being rolled, it is essential for economical running that the times for changing the section should be reduced, and such reduction can be obtained substantially by pre-arranging the rolling stand while the preceding section is still being processed.
DE TS 338.426 and FR 1.549.753 disclose two rolling stands positioned at 90.degree. to each other and having their axis of rotation at the point of union of the axes on which they are positioned.
To replace one or the other stand by a 90.degree. rotation, it is necessary to withdraw the adapters and reposition them.
Moreover, the rolled stock passes in the neighbourhood of the stand during maintenance and re-equipment, with serious danger for the machine operators. These embodiments therefore entail long re-equipment times and danger for the machine operators.
DE PS 687.920 discloses an auxiliary unit located momentarily in front of a rolling stand, this auxiliary unit serving to facilitate the withdrawal of two working rolls and their replacement with a fresh pair of rolls taken from a store. This device speeds up the replacement of the pair of rolls but leaves the position of the stand unchanged and does not permit work to be carried out on the roll housings unless the stand is halted.
DE 693.225 discloses two pairs of rolls which are mutually replaceable either by being slid into position or by being rotated. The proposed embodiments always provide for the previous removal and subsequent reattachment of the adapters. Moreover, the maintenance or replacement work is performed in an area which involves danger for the machine operator.
DE 875.035 discloses rapid means to adjust the rolling pressure on rolling stands.
DE 1.054.409 discloses two sets of stands which are made to rotate so as to take up alternately a reciprocal working position and a maintenance and re-equipment position.